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  • Column liquid chromatography  (495)
  • photosynthesis  (262)
  • taxonomy  (246)
  • Springer  (1,003)
  • 2000-2004  (117)
  • 1990-1994  (886)
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  • 1
    ISSN: 1439-0361
    Keywords: Biogeography ; geographic variation ; taxonomy ; Amazilia ; Trochilidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Die vorliegende Studie stellt die Ergebnisse von Untersuchungen zur Biogeographie, geographischen Variation, Habitatwahl und Taxonomie der Lesson-Amazilie (Amazilia amazilia) vor. Das Taxon umfaßt gegenwärtig fünf Unterarten, die von W-Ecuador bis SW-Peru verbreitet sind und überwiegend submontane Lebensräume besiedeln. Die Ventralfärbung unterliegt klinaler Variation; weiße Gefiederanteile nehmen von nördlichen zu südlichen Populationen ab, rotbraune Partien dagegen zu. Eigenständige morphologisch-morphometrische Kennzeichen sowie Unterschiede in den Habitatpräferenzen und in der Gesangsstruktur rechtfertigen es, die bisherige UnterartA. a. alticola als Paraspezies (A. alticola, Loja-Amazilie) anzuerkennen. Der Vulgärname weist auf den rezenten Verbreitungsschwerpunkt in den südecuadorianischen Anden hin. Aufgrund der engen Verwandtschaft bildenA. amazilia undA. alticola sowie die in Kolumbien endemische ArtA. castaneiventris eine Superspezies.
    Notes: Summary This paper reviews the biogeography, geographic variation, and habitat characteristics of the Amazilia Hummingbird (Amazilia amazilia). Based on morphological features, habitat preferences, and bioacoustics, I propose that the currently recognized subspeciesA. a. alticola should be regarded as a species distinct fromA. amazilia. Synapomorphic characters found in both taxa indicate membership of the same superspecies, together with the Colombian speciesA. castaneiventris. Considering the distributional focus ofA. alticola in the Andes of southern Ecuador, the English species name Loja Hummingbird is suggested.
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  • 2
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    Journal of ornithology 141 (2000), S. 275-284 
    ISSN: 1439-0361
    Keywords: East Asia ; taxonomy ; species delimitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Über die Gliederung der ostasiatischen Dickschnabelkrähen (Corvus macrorhynchos s.l.) in Biospezies besteht bisher keine einhellige Meinung. In dem großen Verbreitungsgebiet zwischen Indien, Japan und Timor werden gegenwärtig eine, zwei oder drei Arten anerkannt. Hier versuchen wir, in akustischen Merkmalen artanzeigende Merkmale zu finden. Eine Diskriminanzanalyse der Rufstruktur (76 Parameter) trennt dreiCorvus-Taxa (levaillantii undjaponensis aus der ‘macrorhynchos-Gruppe’,splendens) von der Südabdachung des Himalaya (Nepal, Kashmir) vollständig voneinander. BeiC. japonensis bleiben die trennenden Merkmale über große geographische Gebiete konstant. Die akustischen Unterschiede werden als taxonomisch relevant angesehen; sie zeigen Artgrenzen an. Folglich werden die Dickschnabelkrähen aus den Tief- und Hochlagen Nepals (Kontaktzone um 2 000 m) zwei Biospezies zugeordnet (C. japonensis undC. levaillantii), in Übereinstimmung mit morphologischen, ökologischen und parasitologischen Daten. Taxonomische Extrapolation der Befunde auf die Systematik anderer ‘macrorhynchos’-Populationen erscheint über die Rufstruktur (bis zum Fernen Osten Rußlands) und über Federling-Parasiten (Mallophaga) auf große Teile SO-Asiens möglich, bedarf aber für die stimmlichen Merkmale noch weiterer Klärung. Wahrscheinlich müssen immacrorhynchos-Komplex mindestens drei biologische Arten anerkannt werden (C. japonensis, C. levaillantii, C. macrorhynchos s. str.).
    Notes: Summary A discriminant analysis of the call structure completely separates threeCorvus taxa (levaillantii andjaponensis of the ‘macrorhynchos group’,splendens) inhabiting the southern slopes of the Himalayas (Nepal, Kashmir). The acoustic differences are considered taxonomically relevant, indicating species boundaries. Therefore the Jungle Crows of lower and upper Nepal (contact zone at around 2,000 m) are assigned to two biospecies (C. japonensis andC. levaillantii), as is consistent with morphological, ecological and parasitological data. It appears possible to extrapolate the findings regarding call structure to the systematics of other ‘macrorhynchos’ populations as distant as the Russian Far East, and those regarding mallophagan parasites to large areas of SE Asia; regarding the vocal characteristics, however, further clarification is needed.
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  • 3
    ISSN: 1570-7458
    Keywords: Vitis vinifera ; Empoasca vitis ; leafhopper ; photosynthesis ; transpiration ; stomatal conductance ; mesophyll conductance ; growth ; yield ; fruit quality ; starch ; carbohydrate reserves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The impact of the grape leafhopper,Empoasca vitis, on leaf gas exchange, plant growth, yield, fruit quality and carbohydrate reserves of the grapevines,Vitis vinifera L., was studied. Gas exchange was measured on the discolored (red) and the green parts of infested main leaves and on leaves from uninfested vines. Photosynthesis and mesophyll conductance were severely reduced on main leaves showing leafhopper feeding symptoms. The stomatal conductance of the red leaf section of infested main leaves was lower than on undamaged control leaves. Additionally, the red leaf section of infested main leaves showed lower transpiration rates when compared to the green parts of the same leaves and to undamaged control leaves. Gas exchange processes of lateral leaves were not affected by leafhopper feeding. Leafhopperload on main leaves was correlated to visual damage symptoms. At 71.8 leafhopper-days per leaf up to 40% of the main leaf area of the infested plants was discolored from the borders towards the center. Lateral leaves showed no feeding symptoms. Shoot diameter, pruning weight and carbohydrate reserves in the wood were not affected by leafhoppers. Lateral leaf area growth was significantly stimulated on plants infested by leafhoppers. No decrease in yield and fruit quality with leafhopper-loads up to 71.8 leafhopper-days per leaf were observed.
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  • 4
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    Entomologia experimentalis et applicata 63 (1992), S. 101-102 
    ISSN: 1570-7458
    Keywords: Cnaphalocrosis medinalis ; rice leaffolder ; Oryza sativa ; rice ; photosynthesis ; transpiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 5
    ISSN: 1572-8773
    Keywords: Chorella vulgaris ; acid tolerance ; ATPase ; nickel toxicity ; nutrient uptake ; photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract This study concerns the inhibitory effects of acid pH and nickel on growth, nutrient (NO3 - and NH4 +) uptake, carbon fixation, O2 evolution, electron transport chain and enzyme (nitrate reductase and ATPase) activities of acid tolerant and wild-type strains of Chlorella vulgaris. Though a general reduction in all these variables was noticed with decreasing pH, the tolerant strain was found to be metabolically more active than the wild-type. A reduced cation (NH4 +, Na+, K+ and Ca2+) uptake, coupled with a facilitated influx of anions (NH4 +, PO4 3- and HCO3 -), suggested the development of a positive membrane potential in acid tolerant Chlorella. Nevertheless, a tremendous increase in ATPase activity at decreasing pH revealed the involvement of superactive ATPase in exporting H+ ions and keeping the internal pH neutral. A difference in Na+ and K+ efflux of the two strains at decreasing pH suggests there is a difference in membrane permeability. The low toxicity of Ni in the acid tolerant strain may be due to the low Ni uptake brought about by a change in membrane potential as well as in permeability. Hence, the development of superactive ATPase and a change in both membrane potential and permeability not only offers protection against acidity, but also co-tolerance to metals.
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  • 6
    ISSN: 1420-9055
    Keywords: Phytoplankton ; primary production ; photosynthesis ; optics ; adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This tutorial was designed for nonbiologists requiring an introduction to the nature and general timescales of phytoplankton responses to physical forcing in aquatic environments. As such, an effort was made to highlight biological markers which might assist in identifying, measuring and/or validating physical processes controlling the variability in the distribution, abundance, composition and activity of phytoplankton communities. Given the recent advances in environmental optics and remote sensing capabilities, a special emphasis was placed on the nature and utility of phytoplankton optical properties in current bio-optical modelling efforts to predict temporal and spatial variability in phytoplankton productivity and growth.
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  • 7
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    BioMetals 5 (1992), S. 149-156 
    ISSN: 1572-8773
    Keywords: Hg2+ toxicity ; cyanobacterium ; Nostoc calcicola ; growth ; photopigments ; nucleic acids ; photosynthesis ; membrane integrity ; nutrient uptake ; enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Toxicological responses of the filamentous N2-fixing cyanobacteriumNostoc calcicola Bréb. towards Hg2+ were studied to enumerate the decisive lethal events. In low-dose, long-term experiments (0.05–0.25 μm Hg2+, 10 days), photoautotrophic growth was severely inhibited with concurrent loss of photosynthetic pigments (phycocyanin〉chlorophyll α〉carotenoids) and nucleic acids. The termination of growth after a day 4 exposure to 0.25 μm Hg2+ has been attributed to the complete inhibition ofin vivo photosynthetic activity in the cyanobacterium (O2 evolution〉14CO2 incorporation). The elevated Hg2+ concentrations irreversibly damaged the cell membrance as observed under light microscopy, and as indicated by the leakage of intracellular electrolytes and phycocyanin. In high-dose, short-term experiments (0.5–20.0 μm Hg2+, up to 6 h), thein vivo activities of selected enzymes (glutamine synthetase 〉 nitrate reductase 〉 nitrogenase) were less inhibited by Hg2+ than the uptake of nutrient ions (NH 4 + 〉NO 3 − 〉PO 4 3− ).
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  • 8
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    Conservation genetics 1 (2000), S. 67-76 
    ISSN: 1572-9737
    Keywords: mitochondrial DNA ; phylogeny ; phylogeography ; speciation ; species concepts ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 9
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    Journal of paleolimnology 9 (1993), S. 63-68 
    ISSN: 1573-0417
    Keywords: Chrysophyceae ; stomatocysts ; membrane topography ; biogenic silica deposition ; surface pattern ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
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  • 10
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    Journal of paleolimnology 6 (1991), S. 257-260 
    ISSN: 1573-0417
    Keywords: Chrysophyceae ; stomatocysts ; biogenic silica deposition ; polymer gels ; surface pattern ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract The utility of classifying chrysophyte stomatocysts by their characteristic honeycomb and ridge patterns is questioned, because a strikingly similar expanding pattern appears on the surface of ionized polymer gels during osmotical swelling as a result of simple physical forces. The rapid accumulation of silicate into a spherical cyst inside a chrysophyte cell appears to be as a physical process sufficiently similar to result in an analogous pattern in microscopic scale. Chrysophyte stomatocysts that possess honeycomb or ridge patterns could be regarded as ‘frozen moments’ of the pattern evolution during the silicate gel phase. As a consequence, such structures should have little taxonomical value.
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  • 11
    ISSN: 1573-0832
    Keywords: DNA ; Exophiala dermatitidis ; Exophiala gougerotii ; Exophiala jeanselmei ; mitochondria ; restriction profiles ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Mitochondrial DNA (mtDNA) analysis with Hae III, Hind. III and Msp I was performed in 45 Exophiala jeanselmei strains (30 Phialophora jeanselmei and 15 Phialophora gougerotii strains) and 31 Exophiala dermatitidis strains. The results were as follows, 1) P. jeanselmei and P. gougerotii are identical, 2) E. jeanselmei is classified into 18 types based on restriction profiles, 3) two strains of E. jeanselmei CBS 577.76 and CBS 578.76 are identified as E. dermatitidis, 4) E. dermatitidis has no intraspecific variation and is definitely distinct from E. jeanselmei, 5) E. jeanselmei is suggested to be a complex organism because of extensive mtDNA polymorphism.
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  • 12
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    Antonie van Leeuwenhoek 57 (1990), S. 223-236 
    ISSN: 1572-9699
    Keywords: fluorescent Pseudomonas ; root associated ; siderophores ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The phenetic taxonomy of 110 fluorescent bacterial strains, isolated from the roots of tomatoes and other plants was numerically studied through 97 features including 69 assimilation tests. Thirty-two reference strains of various Pseudomonas spp. were additionally included. The strains clustered into 16 clusters at the 74% similarity level when using Jaccard similarity coefficients. Almost all field strains belonged to the P. fluorescens/P. putida-complex while none clustered with P. syringae and allied bacteria. The biovar II branch, as well as the newly described biovar VI of P. fluorescens, made up 55% and 20% respectively, of the field strains; two % were allocated to P. fluorescens biovar I and three % to biovar IV. Eleven % of the root associated strains were designated P. putida; six strains were biovar A, three strains biovar B while four strains could not be referred to any known biovar. The continuum within the P. fluorescens/P. putida-complex as well as the taxonomic status of the six biovars of P. fluorescens and the three biovars of P. putida are discussed.
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  • 13
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    Antonie van Leeuwenhoek 58 (1990), S. 95-98 
    ISSN: 1572-9699
    Keywords: Zygozyma smithiae ; Lipomycetaceae ; ambrosia yeasts ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new species of the genus Zygozyma, Z. smithiae, was recovered from frass of the ambrosia beetle, Crossotarsus externedentatus in Northern Natal. A description of the new species and key to the genus are given.
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  • 14
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    Antonie van Leeuwenhoek 57 (1990), S. 59-61 
    ISSN: 1572-9699
    Keywords: Arxula ; Candidaceae ; yeasts ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The new genus Arxula is proposed for the classification of xerotolerant, ascomycetous, anamorphic, arthroconidial yeasts. The genus is considered to be of endomycetaceous affinity.
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  • 15
    ISSN: 1572-9699
    Keywords: basidiomycetous yeasts ; Kurtzmanomyces tardus ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new yeast species of basidiomycetous affinity Kurtzmanomyces tardus was isolated from contaminated demineralized water. It differs from K. nectairii, the only other Kurtzmanomyces species so far described, in its carbon assimilation pattern and low DNA-DNA homology (2.3%±2.1).
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  • 16
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    Antonie van Leeuwenhoek 61 (1992), S. 245-248 
    ISSN: 1572-9699
    Keywords: Sporobolomyces lactosus ; yeasts ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new species of ballistospore-forming yeasts was recovered and its description given.Sporobolomyces lactosus, isolated from activated sludge treating petrochemical wastes, produces pinkish-coral to pink colored colonies, assimilates lactose and has Q-10 as the major ubiquinone.
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  • 17
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    Antonie van Leeuwenhoek 61 (1992), S. 289-316 
    ISSN: 1572-9699
    Keywords: Trichosporon ; white piedra ; systemic mycosis ; taxonomy ; nDNA ; rRNA ; ubiquinone systems ; basidiomycetous yeasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The genusTrichosporon was revised using characters of morphology, ultrastructure, physiology, ubiquinone systems, mol% G+C of DNA, DNA/DNA reassociations and 26S ribosomal RNA partial sequences. A total of 101 strains was used, including all available type and authentic cultures of previously described taxa. Nineteen taxa could be distinguished, 15 of which having Q-9 coenzyme systems and 4 having Q-10. Sixteen previously described names were reduced to synonymy. One new species was described. The genus is characterized by the presence of arthroconidia. Few species possess further diagnostic morphological characters, such as the presence of appressoria, macroconidia or meristematic conidiation. The septa of two species were found to be non-perforate, while those of the remaining species contained dolipores at variable degrees of differentiation, with or without vesicular or tubular parenthesomes. All species were able to assimilate a large number of carbon compounds; visible CO2 production was absent. The genus was found to be fairly homogeneous on the basis of a phylogenetic analysis of partial 26S rRNA sequences, with the exception ofT. pullulans which proved to be unrelated. Most taxa were found to occupy well-defined ecological niches. Within the group of taxa isolated from humans, a distinction found be made between those involved in systemic mycoses and those which mainly caused public or non-public white piedras, respectively. One species was consistently associated with animals, while others came mainly from soil or water. One species was mesophilic and another psychrophilic.
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  • 18
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    Antonie van Leeuwenhoek 66 (1994), S. 337-342 
    ISSN: 1572-9699
    Keywords: Debaryomyces ; phylogeny ; ribosomal RNA ; taxonomy ; Wingea ; yeasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Extent of divergence in partial nucleotide sequences from large and small subunit ribosomal RNAs was used to estimate the evolutionary relationship between the generaWingea andDebaryomyces. These data showed the monotypic genusWingea to be congeneric withDebaryomyces, and it is proposed to transferW. robertsii toDebaryomyces.
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  • 19
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    Journal of the history of biology 33 (2000), S. 27-70 
    ISSN: 1573-0387
    Keywords: ants ; E. O. Wilson ; Ernst Mayr ; systematics ; Systematics and the Origin of Species ; taxonomy ; William L. Brown ; William Morton Wheeler ; William Steel Creighton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , History
    Notes: Abstract Ideas about the natural world are intertwined with the personalities, practices, and the workplaces of scientists. The relationships between these categories are explored in the life of the taxonomist William Steel Creighton. Creighton studied taxonomy under William Morton Wheeler at Harvard University. He took the rules he learned from Wheeler out of the museum and into the field. In testing the rules against a new situation, Creighton found them wanting. He sought a new set of taxonomic principles, one he eventually found in Ernst Mayr's Systematics and the Origin of Species. Mayr's ideas tied together a number of themes running through Creighton's life: the need for a revised taxonomy, the emphasis on fieldwork, and the search for a new power center for ant taxonomy after Wheeler died. Creighton's adoption of Mayr's ideas as part of his professional identity also had very real implications for his career path: field studies required long and intensive studies, and Creighton would always be a slow worker. His method of taxonomy contrasted sharply not only with Wheeler's but also with two of his younger colleagues, William L. Brown and E. O. Wilson, who took over Wheeler's spot at Harvard in 1950. The disputes between these men over ant taxonomy involved, in addition to questions of technical interest, questions about where and how best to do taxonomy and who could speak withthe most authority. Creighton's story reveals how these questions are interrelated. The story also reveals the importance of Mayr's book for changes occurring in taxonomy in the middle of the twentieth century.
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  • 20
    ISSN: 1420-9098
    Keywords: Thaumatomyrmex ; taxonomy ; comparative morphology ; predation ; Polyxenidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We describe, for the first time, the predatory behaviour ofThaumatomyrmex ants on millipedes of the family Polyxenidae, based on field observations ofT. atrox and a field and laboratory study ofT. contumax. The capture of the prey and the removal process of its body-covering setae by the ants before they eat the millipede are described. This specialized behaviour in at least two species of the genus, belonging to two distinct groups of species, indicates a general trend inThaumatomyrmex. We coupled this study with a comparative morphological analysis of the mouthparts and digestive tube of these and otherThaumatomyrmex species. Also, we report the first case of sympatry in the genus, which suggests thatThaumatomyrmex includes several species, and not only one highly variable taxon, as hypothetized earlier.
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  • 21
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    Cellular and molecular life sciences 49 (1993), S. 1055-1058 
    ISSN: 1420-9071
    Keywords: Moderate halophiles ; taxonomy ; Salinicoccus roseus ; Marinococcus hispanicus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The Gram-positive moderately halophilic cocci validly described up to date areMicrococcus halobius, Sporosarcina halophila, Marinococcus halophilus, Marinococcus albus, Marinococcus hispanicus, and the recently proposedSalinicoccus roseus. Our chemotaxonomic studies on these bacteria have revealed thatMarinococcus hispanicus should be placed in the genusSalinicoccus. DNA-DNA hybridization studies showed that this species should be considered as a separate species ofS. roseus. Thus, we have proposed transferring it to the genusSalinicoccus, asS. hispanicus. Besides, phenotypic and chemotaxonomic features of the culture collection moderate halophilesMicrococcus sp. strains CCM 168 and CCM 1405 indicate that they should be included in the speciesSalinicoccus roseus. The description of this species was based only on one strain.
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  • 22
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    Aquatic sciences 54 (1992), S. 321-330 
    ISSN: 1420-9055
    Keywords: Algal pigments ; algal communities ; photosynthesis ; Lake Lugano (Lago di Lugano)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A one-year study of phytoplankton, primary production and related physical and chemical factors was made in a Swiss basin of Lake Lugano (Lago di Lugano). The chlorophylls and 12 carotenoids were analyzed with a TLC technique. The carotenoid monitoring was considered to be particularly interesting, because the role of these pigments in freshwater algae is still very poorly documented by field studies. The dependence of photosynthesis on several factors was statistically evaluated. Evidence was found of light-adaptation phenomena. The variations of photosynthetic activity and efficiency largely depended on the light regime in the few days before the field observations and on the cellular content of chlorophylls and single carotenoids, whose concentrations in their turn were closely linked with light, temperature, average cell size, and with the actual species assemblage.
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  • 23
    ISSN: 1420-9055
    Keywords: Heterotrophic bacteria ; sediments ; taxonomy ; seasonal variations ; aerobic bacterial population ; anaerobic bacterial population ; Lake Lugano (Lago di Lugano)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This research was carried out with the aim to explore the heterotrophic microbial population of two sediments in different oxic conditions of the Lake of Lugano (Lago di Lugano). The values of the viable bacterial counts found in our sediment samples were typical for an eutrophic lake. The increase in the proportion of anaerobic to aerobic bacteria at 30 °C observed in the sediment samples of Agno may reflect the depletion of oxygen concentrations in the water column. The generaAeromonas, Pseudomonas, Bacillus andClostridium, as well as strains belonging to the Coryneform-group, represented the major taxonomic groups of heterotrophic bacterial communities in the water-sediment interface.
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  • 24
    ISSN: 1440-1703
    Keywords: Clethra barbinervis ; interspecific difference ; intraspecific variation ; photosynthesis ; SO2 resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of SO2 on the photosynthesis ofClethra barbinervis collected from a smoke-polluted area near the Ashio copper smelter in Tochigi Prefecture was compared withC. barbinervis collected from a nonpolluted district in Tsukuba, Ibaraki Prefecture andQuercus mongolica var.grosseserrata grown in a nonpolluted field in Nagano Prefecture. The plants were exposed to 0.5–1.5 p.p.m. SO2 for 90 min (short-term) and to 0.3 p.p.m. SO2 for 31–39 days (long-term). TheClethra plants from both sites had a lower intrinsic stomatal conductance and photosynthetic rate thanQuercus plants. Short-and long-term fumigation caused stomatal closure inQuercus plants, but had little effect on the stomatal conductance ofClethra plants. Under short-term fumigation, nonstomatal photosynthetic inhibition per unit of absorbed SO2 was smallest inClethra plants from Ashio. Long-term fumigation caused photosynthetic decline and visible foliar injury toQuercus plants, but had no effect onClethra plants from Ashio. Consequently,Clethra plants from Ashio had a higher photosynthetic rate thanQuercus plants after long-term fumigation. These results suggest thatC. barbinervis populations in the smoke-polluted area of Ashio had evolved high SO2 resistance connected with SO2 detoxification ability in mesophyll cells.
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  • 25
    ISSN: 1440-1703
    Keywords: photosynthesis ; Prunus avium ; relative growth rate ; shading ; total plant water use efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Cherry (Prunus avium L.) saplings were grown under natural sunlight (controls) or moderate shading (up to 30%, depending on the incident light intensity and the hour of the day). Reduced light intensity increased the dry mass of each of the plant components studied. Consequently, the total dry mass of shaded plants was significantly greater than that of controls at the end of the growing season. However, the diurnal trend in the level of photosynthesis (per unit of leaf area) of shaded plants was similar to the controls in August, but lower in September. As the growing season proceeded, reduced photosynthetic rates, thinner mesophyll and larger specific leaf area in the shaded plants indicated that leaf development had adapted to shaded conditions throughout the growing season. It is suggested that increased growth of shaded plants was caused by a higher initial relative growth rate and a greater whole-plant photosynthesis. Shading consistently reduced transpiration over the season, therefore improving water use efficiency of shaded leaves. Our results suggest that a moderate reduction in light intensity can be a useful method for improving growth and saving water in hot and dry environments.
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  • 26
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    Ecological research 8 (1993), S. 81-83 
    ISSN: 1440-1703
    Keywords: bract ; Carpinus laxiflora ; mast year ; photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Light saturated net photosynthesis was measured in bracts and leaves ofCarpinus laxiflora, the major species in secondary forests in cool and intermediate temperate zones in Japan. The maximum net photosynthesis of leaves and bracts was essentially constant from May to early August and decreased gradually thereafter. For bracts, it was 3.2 μmol m−2s−1, approximately half that for the leaves. The photosynthesis of bracts would thus appear to contribute significantly to seed maturity. The estimated production of bract based on the photosynthesis would make seeds (3 mg dry weight) mature for 37 days, assuming all photosynthate of the bracts to have been distributed in the seeds only. This was quite consistent with the growth curve for the seeds. A mast year phenomenon is discussed in relation to bract photosynthesis and leaf number.
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  • 27
    ISSN: 1440-1703
    Keywords: Aucuba japonica ; photosynthesis ; Sea of Japan ; shading ; snow cover
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    Topics: Biology
    Notes: Abstract Aucuba japonica varieties are common evergreen understory shrubs in Japan.Aucuba japonica var.borealis is distributed on the Sea of Japan side of Honshu and Hokkaido where heavy snow cover lasts for more than 3 months in winter.Aucuba japonica var.japonica is distributed in areas with shallow or no snow on the Pacific Ocean side of Honshu and Shikoku. The ecophysiological characteristics of var.borealis were compared with those of var.japonica to examine the effects of heavy and long-term snow cover on the life cycle of var.borealis. Shoots of both varieties were shaded in crushed ice for 110 days, but their photosynthetic activities, chlorophyll contents and the chlorophylla/b ratio was not affected. The leaves of var.borealis were no less frost tolerant than those of var.japonica. In spite of the difference in environmental factors, both varieties had similar characteristics in seasonal changes of photosynthesis, respiration and chlorophylla/b ratio. These results suggest that var.japonica could survive in areas with heavy snow where it does not normally occur. Leaf net production (LNP) was estimated based on the microclimatic data and seasonal photosynthetic and respiration rates. The difference in the annual LNP between the two varieties was equivalent to the difference in the LNP during the snow season. One of the major effects of snow cover is to interrupt and reduce the production period of var.borealis.
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  • 28
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    World journal of microbiology and biotechnology 10 (1994), S. 88-92 
    ISSN: 1573-0972
    Keywords: Intelligent screening ; microbial hydroxylation ; multivariate analyses ; taxonomy ; terpenoids
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    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Forty strains of bacteria and 60 of fungi were screened with globulol, 1,8-cineol and cedrol and the strains compared, on the basis of the resulting products, using multivariate analyses. The taxonomic position of the strains is mirrored in their biotransformation capability. Fungi and bacteria, fungal phyla, and Gram-positive and-negative bacteria could all be distinguished in a discriminant analysis using 12 substrates. Hierarchical clustering yielded five groups of strains with distinct biotransformation activity. Such clustering will allow a more efficient screening than before.
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  • 29
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    Journal of chemical ecology 19 (1993), S. 559-568 
    ISSN: 1573-1561
    Keywords: Juglone ; allelopathy ; allelochemical ; photosynthesis ; chioroplast ; mitochondria ; Lemna minor ; Glycine max
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The impacts of juglone on plant growth and several other physiological functions were evaluated in this study. Juglone inhibitedLemna minor growth, chlorophyll content, and net photosynthesis at treatments between 10 and 40μM. Soybean leaf disks vacuum infiltrated with as little as 10μM juglone had reduced photosynthesis. Oxygen evolution by chloroplasts isolated fromPisum sativum was inhibited by juglone with an I50 of 2μM. Micromolar treatments of juglone stimulated oxygen uptake in mitochondria isolated fromGlycine max. These data suggest perturbations of chloroplast and mitochondrial functions may contribute to plant growth reductions observed in juglone-mediated allelopathy.
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  • 30
    ISSN: 1573-1561
    Keywords: Coleoptera ; Staphylinidae ; Tenebrionidae ; larvae ; defensive glands ; quinone ; naphthoquinone ; taxonomy
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The abdominal glands of three bark-inhabiting larvae of generaBolitochara, Leptusa (Staphylinidae), andHypophloeus (Tenebrionidae) were studied chemically and morphologically. Behavior of the larvae indicated that secretion is emitted only after severe disturbance of the larvae. These mechanical contacts may also occur incidentally with coinhabiting nonpredatory arthropods when the beetle larvae move within small interstices under bark. Depending on the species, the secretions contained 1,4-benzoquinone derivatives and three 6-alkyl-naphthoquinones dissolved within various alkanes, alkenes, ethyl-, isopropyl-, and isoamylesters. More erratically distributed gland constituents also detected were acetophenone, benzyl propionate, and methyl hydroxybenzoate. In the laboratory, synthetic quinone-containing solutions simulating those found inLeptusa andBolitochara larvae acted as strong topical irritants and caused further damage to last-stageCalliphora vomitoria larvae if hydrocarbons or esters were used as solvents. The natural secretions ofHypophloeus versipellis elicited considerable mortality in two subcortical sciarid larvae cooccurring with tenebrionid larvae. Bioassay and secretion chemistry of the Staphylinidae/Tenebrionidae larval secretions indicated that they are typical defensive secretions that act topically. Morphological data characterized Bolitocharini larvae as possessing protuberant abdominal tergites supplied with an interiorly situated gland reservoir. After mechanical contact, the defensive secretion is topically applied to other arthropods by dabbing this tergal protuberance on targets. The defensive gland ofHypophloeus versipellis is unusual in possessing a movable reservoir opening situated at the anterior border of tergite IX. By this peculiar gland morphologyHypophloeus larvae are capable of shooting secretion droplets frontally from their slightly depressed dorsal abdominal surface without bending their abdominal tips dorsally. This seems an adaptation to the interstitial habitat of the larvae. The types of defensive glands and their phylogenetic value in Aleocharinae/Tenebrionidae larvae are discussed.
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  • 31
    ISSN: 1573-5028
    Keywords: gene duplication ; photosynthesis ; RFLP ; Southern blots
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    Topics: Biology
    Notes: Abstract A second locus (Lhb1B) encoding Photosystem II Type I chlorophyll a/b-binding (CAB) polypeptides was identified in Arabidopsis thaliana. This locus carries two genes in an inverted orientation. The predicted sequences of the polypeptides encoded by these two genes show substantial divergence in their amino termini relative to each other and to the proteins encoded by the three Lhb1 CAB genes previously characterized [10], but little divergence within the predicted primary structure of the mature protein. DNA probes derived from seven additional types of tomato CAB genes, encoding chlorophyll a/b-binding polypeptides of several antenna systems of the photosynthetic apparatus, were tested against A. thaliana. Each of these hybridized in Southern blots to unique DNA fragment(s), demonstrating the existence of each of these different types of CAB genes in the genome of A. thaliana. The number of genes encoding each CAB type in A. thaliana was estimated to be similar to that of tomato.
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  • 32
    ISSN: 1573-5028
    Keywords: carbonic anhydrase ; antisense ; over-expression ; tobacco ; photosynthesis
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    Topics: Biology
    Notes: Abstract The activity and location of carbonic anhydrase has been modified by transformation of tobacco with antisense and over-expression constructs. Antisense expression resulted in the inhibition of up to 99% of carbonic anhydrase activity but had no significant impact on net CO2 assimilation. Stomatal conductance and susceptibility to water stress appeared to increase in response to the decline in carbonic anhydrase activity. An over-expression construct designed to increase cytosolic carbonic anhydrase abundance resulted in a significant increase in net activity, a small increase in stomatal conductance but little impact on CO2 assimilation. Chloroplastic carbonic anhydrase activity was enhanced by the expression of an additional construct which targeted the polypeptide to the organelle. The increase in chloroplastic carbonic anhydrase appeared to be accompanied by a concomitant increase in Rubisco activity.
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  • 33
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    Plant molecular biology 20 (1992), S. 481-491 
    ISSN: 1573-5028
    Keywords: photosynthesis ; cytochrome b 6 ; gene regulation ; genome mapping
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    Topics: Biology
    Notes: Abstract The genes encoding the photosynthetic cytochrome b 6 (petB) and subunit 4 (petD) have been cloned and sequenced from the unicellular, photoheterotrophic, transformable cyanobacterium Synechococcus sp. PCC 7002, formerly designated Agmenellum quadruplicatum. The gene arrangement was found to be similar to that reported in the cyanobacterium Nostoc PCC 7906. The DNA and derived protein sequences were compared to chloroplast and the other cyanobacterial sequences. By pulsed-field electrophoresis, the petBD operon and the petCA operon, encoding the Rieske iron-sulfur protein and cytochrome f, were found to be located on separate, unlinked,Not I-digested DNA fragments. ThepetBD operon was found on the third largest Not I fragment (NC-325) while the petCA operon was found on the second largest Not I fragment (NB-370). These results suggest the two operons are not in proximity. The 1.35 kb transcript was shown to be light-regulated. Transcripts from cells grown under constant illumination showed a decrease in petB transcript levels to undetectable levels within 2 h after the cells were placed in the dark. Upon reillumination, transcript levels rose to three-fold over that seen initially under constant illumination.
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  • 34
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    Plant molecular biology 21 (1993), S. 363-373 
    ISSN: 1573-5028
    Keywords: eukaryotic ; arbitrary oligonucleotide primer ; PCR ; prokaryotic ; silver staining ; taxonomy
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    Topics: Biology
    Notes: Abstract The Azolla-Anabaena symbiosis has been used for centuries as a nitrogen biofertilizer in rice paddies. Genetic improvement of the symbiosis has been limited by the difficulty in identifying Azolla-Anabaena accessions and Anabaena azollae strains. The recently developed technique of DNA amplification fingerprinting (DAF) was applied to this problem. DAF uses single, short, oligonucleotide primers of arbitrary sequence to direct amplification of a characteristic set of DNA products by a thermostable DNA polymerase in a thermocycling reaction. The products are separated in polyacrylamide gels and detected by silver staining. DAF could easily distinguish and positively identify accessions of Azolla-Anabaena with DNA extracted from the intact symbioses. The contribution of prokaryotic Anabaena sequences to the fingerprint of the intact symbioses, however, ranged from 0 to 77%, depending on the primer sequence. Therefore, DNA extracted from the intact symbioses would not be suitable for Azolla taxonomy studies. The fingerprints of Anabaena strains isolated by sucrose gradient centrifugation from different species of Azolla could be easily distinguished, and DAF patterns were used to confirm the maternal pattern of transmission of Anabaena in a sexual hybrid. Template DNA extracted from roots was used to produce fingerprints for Azolla without interference from the microsymbiont. Comparison of the patterns from the parents and a hybrid gave strong evidence confirming sexual hybridization.
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  • 35
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    Bioscience reports 11 (1991), S. 539-571 
    ISSN: 1573-4935
    Keywords: proton translocation ; respiration ; photosynthesis ; quinones ; bc complexes ; cytochrome oxidase ; NADH-quinone oxidoreductase
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Detailed molecular mechanisms of electron transfer-driven translocation of ions and of the generation of electric fields across biological membranes are beginning to emerge. The ideas inherent in the early formulations of the chemiosmotic hypothesis have provided the framework for this understanding and have also been seminal in promoting many of the experimental approaches which have been successfully used. This article is an attempt to review present understanding of the structures and mechanisms of several osmoenzymes of central importance and to identify and define the underlying features which might be of general relevance to the study of chemiosmotic devices.
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  • 36
    ISSN: 1573-5028
    Keywords: chlorophyll-binding proteins ; photosynthesis ; photosystem II ; site-directed mutagenesis ; Synechocystis
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    Topics: Biology
    Notes: Abstract A mutant strain of the cyanobacterium Synechocystis sp. PCC (Pasteur Culture Collection) 6803 has been developed in which psbB, the gene coding for the chlorophyl a-binding protein CP47 in Photosystem II (PSII), has been deleted. This deletion mutant can be used for the reintroduction of modified psbB into the cyanobacterium. To study the role of a large hydrophilic region in CP47, presumably located on the lumenal side of the thylakoid membrane between the fifth and sixth membrane-spanning regions, specific deletions have been introduced in psbB coding for regions within this domain. One psbB mutation leads to deletion of Gly-351 to Thr-365 in CP47, another psbB mutation was targeted towards deletion of Arg-384 to Val-392 in this protein. The deletion from Gly-351 to Thr-365 results in a loss of PSII activity and of photoautotrophic growth of the mutant, but the deletion between Arg-384 and Val-392 retains PSII activity and the ability to grow photoautotrophically. The mutant strain with the deletion from Gly-351 to Thr-365 does not assemble a stable PSII reaction center complex in its thylakoid membranes, and exhibits diminished levels of CP47 and of the reaction center proteins D1 and D2. In contrast to the Arg-384 to Val-392 portion of this domain, the region between Gly-351 and Thr-365 appears essential for the normal structure and function of photosystem II.
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  • 37
    ISSN: 1573-5028
    Keywords: cyanobacterial mutant ; membrane assembly ; PsaE ; photosystem I ; photosynthesis
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    Topics: Biology
    Notes: Abstract We studied assembly of the PsaE subunit of photosystem I into photosynthetic membranes of cyanobacterial mutant strains that lack specific photosystem I subunits. Radiolabeled PsaE was incubated with photosynthetic membranes, and their binding and assembly were assayed by resistance to removal by chaotropic agents and proteolytic digestion. PsaE incorporated into the wild-type membranes was resistant to these treatments. In the absence of PsaD, it was resistant to proteolytic digestion, but was removed by NaBr. When the membranes were isolated from a mutant strain in which the psaF and psaJ genes have been inactivated, PsaE assembled in vitro could not be removed. PsaE could associate with the membranes of the strain DF in which the psaD, psaJ and psaF genes have been mutated. However, the radiolabeled PsaE associated with these membranes was removed both by the proteolytic as well as by the chaotropic agents. Characterization of PsaE present in vivo revealed similar results. These observations suggest that PsaD and PsaF/J may interact with PsaE and stabilize it in the photosystem I complex.
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  • 38
    ISSN: 1573-5028
    Keywords: gene expression ; photosynthesis ; protein turnover ; psbA ; tac promoter
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    Topics: Biology
    Notes: Abstract The unicellular cyanobacterium Synechococcus sp. PCC 7942 has three psbA genes encoding two different forms of the photosystem II reaction centre protein D1 (D1:1 and D1:2). The level of expression of these psbA genes and the synthesis of D1:1 and D1:2 are strongly regulated under varying light conditions. In order to better understand the regulatory mechanisms underlying these processes, we have constructed a strain of Synechococcus sp. PCC 7942 capable of over-producing psbA mRNA and D1 protein. In this study, we describe the over-expression of D1:1 using a tac-hybrid promoter in front of the psbAI gene in combination with lacI Q repressor system. Over-production of D1:1 was induced by growing cells for 12 h at 50 μmol photons m-2 s-1 in the presence of 40 or 80 μg/ml IPTG. The amount of psbAI mRNA and that of D1:1 protein in cells grown with IPTG was three times and two times higher, respectively. A higher concentration of IPTG (i.e., 150 μg/ml) did not further increase the production of the psbAI message or D1:1. The over-production of D1:1 caused a decrease in the level of D1:2 synthesised, resulting in most PSII reaction centres containing D1:1. However, the over-production of D1:1 had no effect on the pigment composition (chlorophyll a or phycocyanin/number of cells) or the light-saturated rate of photosynthesis. This and the fact that the total amounts of D1 and D2 proteins were not affected by IPTG suggest that the number of PSII centres within the membranes remained unchanged. From these results, we conclude that expression of psbAI can be regulated by using the tac promoter and lacI Q system. However, the accumulation of D1:1 protein into the membrane is regulated by the number of PSII centres.
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  • 39
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    Plant molecular biology 17 (1991), S. 641-652 
    ISSN: 1573-5028
    Keywords: F-ATPase ; cyanobacteria ; operon ; evolution ; photosynthesis
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    Topics: Biology
    Notes: Abstract The two operons atp1 and atp2, encoding the subunits of the FOF1 ATP-synthase, have been cloned and sequenced from the cyanobacterium Synechocystis sp. PCC 6803. The organization of the different genes in the operons have been found to resemble that of the cyanobacteria Synechococcus sp. PCC 6301 and Anabaena sp. PCC 7120. The Synechocystis FOF1 ATP-synthase has nine subunits. A tenth open reading frame with unknown function was detected at the 5′ end of atp1, coding for a putative gene product similar to uncI in Escherichia coli. A promoter structure was inferred for the Synechocystis atp operons and compared to other known promoters of cyanobacteria. Even though the operon structure of atp1 and atp2 in Synechocystis resembles the corresponding operons of Synechococcus, the amino acid sequences of individual gene products show marked differences. Genetic distances between cyanobacterial genes and genes for ATP-synthase subunits from other species have been calculated and compiled into evolutionary trees.
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  • 40
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    Plant molecular biology 17 (1991), S. 289-293 
    ISSN: 1573-5028
    Keywords: cytochrome b 6-f complex ; photosystem II (Synechocystis PCC 6803) ; photosynthesis ; Rieske Fe-S sequence ; apocytochrome f sequence
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  • 41
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    Plant molecular biology 19 (1992), S. 217-230 
    ISSN: 1573-5028
    Keywords: chlorophyll a/b-binding protein genes ; Glycine ; LHCP II ; photosynthesis ; soybean ; ribulose-1,5-bisphosphate carboxylase genes
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    Topics: Biology
    Notes: Abstract The levels of chlorophyll a/b-binding protein (Cab) gene polysomal poly(A)+ mRNA were quantitated throughout the development of Glycine max L. Cab mRNAs were abundant in young expanding leaves, representing 6.1% of the leaf mRNA population. Lower Cab mRNA levels were present in embryos, stems, and cotyledons of developing seedlings; the lowest levels were found in roots where they accounted for 0.04% of the polysomal poly(A)+ mRNA of this organ. To determine the contribution of different members of the Cab gene family to the Cab mRNA populations, a quantitative S1 nuclease reconstruction assay was developed. Cab3, Cab4, and Cab5 mRNAs were detected in all stages examined during soybean development but their levels underwent differential changes. Cab3 encodes the most abundant Cab mRNA in young leaves, developing embryos, and in Stage VII cotyledons from the developing soybean seedling. The levels of Cab mRNAs were compared to the levels of ribulose-1,5-bisphosphate carboxylase small subunit gene mRNA and differences in their patterns of accumulation were noted. Collectively these data indicate that during soybean embryogenesis developmental control mechanisms supersede light-regulatory signals.
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  • 42
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    The journal of membrane biology 126 (1992), S. 265-275 
    ISSN: 1432-1424
    Keywords: photosynthesis ; thylakoids ; electrochromism ; gramicidin ; conductance ; dimerization
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary The effect of the pore-forming antibiotic gramicidin on pure lipid membranes is well characterized. We studied its action in protein-rich thylakoid membranes that contain less than 25% (wt/wt) acyl lipids. A transmembrane voltage was induced by flashing light, and its decay was measured and interpreted to yield the distribution of gramicidin over thylakoids, its dimerization constant and its single-channel conductance in this membrane. The distribution of gramicidin over the ensemble of thylakoids was immediately homogeneous when the antibiotic was added under stirring, while it became homogeneous only after 20 min in a stirred suspension that was initially heterogeneous. The dimerization constant, 5×1014 cm2/mol, was about 10 times larger than in pure lipid membranes. This was attributed to the upconcentration of gramicidin in the small fractional area of protein free lipid bilayer and further by a preference of gramicidin for stacked portions of the membrane. The latter bears important consequences with regard to bioenergetic studies with this ionophore. As gramicidin was largely dimerized from a concentration of 1 nm (in the suspension) on, the membrane's conductance then increased linearly as a function of added gramicidin. When the negative surface potential at the thylakoid membrane was screened, the conductance of a single gramicidin dimer agreed well with figures reported for bilayers from neutral lipid (about 0.5 pS at 10 mm NaCl). The modulation of the conductance by the surface potential in spinach versus pea thylakoids and between different preparations is discussed in detail.
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  • 43
    ISSN: 1871-4528
    Keywords: collecting expedition ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A joint Argentina/United States expedition collected wild potato (Solanum sect.Petota) germplasm in Argentina between February 4–28 and March 28–April 18, 1990. This was followed by a short expedition between February 27 and March 3, 1991. Collections were made in the Andes Mountains from southern Tucumán Province (27°20′S), south to southern Rio Negro Province (40°52′S) and comprised 88 lots of germplasm of ten species, 76 as true-seed and 12 as tubers. The most important new collections included germplasm ofS. brevidens, S. maglia, S. x rechei andS. venturii. By summarizing details of these collections with those of existing collections, we have been able to suggest future collecting in Argentina.
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  • 44
    ISSN: 1871-4528
    Keywords: water-stress ; photosynthesis ; yield
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Relations between measurements of the slow kinetics of chlorophyll fluorescence and growth and yield were examined in seven potato genotypes grown either fully irrigated or droughted from the time of plant emergence. Drought reduced total dry matter production and yields and increased tuber dry matter concentration. Drought increased harvest index in cv. Spunta, but decreased it in cv. Pentland Crown. Total dry matter production was correlated with each of constant fluorescence, variable fluorescence and the half life of the decay in variable fluorescence. These correlations were determined largely by the effect of treatment, and did not discriminate effectively between genotypes within a treatment.
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  • 45
    ISSN: 1871-4528
    Keywords: water-stress ; photosynthesis ; leaf water potential
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The slow kinetics of chlorophyll fluorescence were examined in seven potato genotypes grown either fully irrigated or droughted from the time of plant emergence. Constant and variable fluorescence (F o andF v respectively) declined with time in plants from both irrigated and droughted treatments, but the decline was greater in droughted than irrigated plants. However, the yield of variable fluorescence (F v/(F o+F v)) was unaffected by the drought treatment. The main effect of drought was upon the quenching of variable fluorescence. Both the half life of the decay of variable fluorescence (q1/2) and the secondary maximum (M) were significantly greater in the droughted plants than in those from the irrigated treatment. Significant differences between genotypes were found forF v/(F o+F v),M andq 1/2. Genotype-by-treatment interactions were non-significant for all the variables examined. Changes in chlorophyll fluorescence transients were not closely related to changes in leaf water potential.
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  • 46
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    Russian journal of marine biology 26 (2000), S. 389-398 
    ISSN: 1608-3377
    Keywords: hermatypic coral ; zooxanthella ; photosynthesis ; respiration ; energy budget
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    Topics: Biology
    Notes: Abstract We analyzed the recent data on the distribution of the photosynthetic energy of zooxanthellae in corals and the models of interactions between the plant and animal cells in the course of matter and energy exchange developed based on this information. The models of energy exchange of animals symbiotic with zooxanthellae are characterized by the following features: (1) A flow chart of carbon or energy fluxes is the main form of representation of the energetics in native symbiotic organisms. (2) The relations between the symbionts are relatively adequately revealed and correspond to the modern notions; however, the intensities of the energy fluxes ascribed to these relations are dependent on the experimental and design methods used by the authors. (3) The inputs into the energy budget consist of the autotrophic production of zooxanthellae and the heterotrophy of the polyp. The energy expenditures comprise excretion, respiration, development, and growth of the animal and algae. (4) The differences between the species, genera, and phyla of animals that develop symbiotic relations with zooxanthellae are confined to the absolute values of energy fluxes in the organism.
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    Mycoscience 41 (2000), S. 15-23 
    ISSN: 1618-2545
    Keywords: Agaricales ; Clitocybe trogioides var.odorifera ; Gerronema nemorale ; Psathyrella cineraria ; taxonomy
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    Topics: Biology
    Notes: Abstract Two new species and one new variety of Agaricales are described and illustrated from central Honshu, Japan:Clitocybe trogioides var.odorifera var. nov. (subgenusCystoclitus sectionCystoclitus), forming white, infundibuliform basidiomata, was collected from leaf litter in theQuercus-Pasania forests;Gerronema nemorale sp. nov. (sectionXanthophylla), forming small, olivaceous, omphalinoid basidiomata, was found on dead fallen twigs in theQuercus-Pasania forests;Psathyrella cineraria sp. nov. (subgenusMycophylla sectionArgillosporae), forming basidiomata covered by detersile, dark grey, fibrillose-squamulose veil, was found on decayed wood ofQuercus myrsinaefolia.
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  • 48
    ISSN: 1618-2545
    Keywords: Diaporthe kyushuensis ; grapevine swelling arm ; Phomopsis vitimegaspora ; taxonomy
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    Topics: Biology
    Notes: Abstract Diaporthe kyushuensis sp. nov. is described and named as the teleomorph of causal fungus of grapevine swelling arm. The anamorph of the fungus isPhomopsis vitimegaspora.
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  • 49
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    Mycoscience 41 (2000), S. 115-122 
    ISSN: 1618-2545
    Keywords: distribution ; Pinus ; Quercus ; taxonomy ; Uredinales
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Asian pine gall rust, which has hitherto been assigned toCronartium quercuum distributed in North America, is described asC. orientale, sp. nov. The spermogonial and aecial states occur on hard pines, and the uredinial and telial states occur on various oaks.Cronartium orientale has globose, almost hyaline basidiospores in contrast to the ellipsoid, yellow-orange ones of North AmericanC. quercuum s.l. Characteristics of the new rust species in morphology, DNA analysis, and host alternation are discussed.
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  • 50
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    Mycoscience 35 (1994), S. 125-129 
    ISSN: 1618-2545
    Keywords: rust fungus ; taxonomy ; Puccinia tarennicola ; Uredinales ; Uredo daphniphylli ; Uredo pipturi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three species of rust fungi were reported based on the specimens collected in the islands of the Yaeyama group and Okinawa, Japan.Puccinia tarennicola onTarenna gracilipes andUredo daphniphylli onDaphniphyllum teijsmannii were described as new species.Villebrunea frutescens was added to the host plants ofUredo pipturi.
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  • 51
    ISSN: 1618-2545
    Keywords: China ; Leptographium ; morphology ; taxonomy ; Tomicus piniperda
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    Topics: Biology
    Notes: Abstract Tomicus species (Coleoptera: Scolytidae) are serious pests of pines with a wide distribution in Europe, Asia and America. In Yunnan, south-western China,T. piniperda has destroyed more than 0.5 million ha ofPinus yunnanensis in the past 15 years. A blue stain fungus belonging to the genusLeptographium is associated with both the shoot-feeding and trunk-attacking stages of the beetle's life cycle. The fungus is morphologically similar to the anamorph ofOphiostoma crassivaginatum and toL. pyrinum, which are both characterised by short robust conidiophores and hyphae covered by a granular layer. Both these species have been isolated from conifers and are associated with insects. After comparing the fungus fromT. piniperda with similarLeptographium species, using light and scanning electron microscopy, we concluded that it represents a new taxon, which is described here asL. yunnanense sp. nov.
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    Plant systematics and evolution 191 (1994), S. 161-170 
    ISSN: 1615-6110
    Keywords: Poaceae ; Puccinellia ; Pollen maximum diameter ; pollen fertility ; taxonomy ; Flora of the Iberian Peninsula
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    Notes: Abstract Diameter and fertility of pollen grains were surveyed in nine species ofPuccinellia Parl. (Poaceae), mainly from the Iberian Peninsula, allowing information about reproductive behaviour and biological characteristics of pollen of these taxa. Maximum diameter was measured with an image processor and fertility was evaluated by staining the grains with Müntzing's mixture. Significant differences in both characters were found between the taxa. In consequence, maximum diameter and fertility proved to have some taxonomic relevance inPuccinellia.
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  • 53
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    Plant systematics and evolution 191 (1994), S. 213-226 
    ISSN: 1615-6110
    Keywords: Poaceae ; Hordeum ; Isoenzymes ; taxonomy ; phylogenetic species ; sibling species
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    Notes: Abstract Morphological differentiation of diploid accessions ofHordeum marinum Huds. s.l. into two varieties, var.marinum and var.fouilladei (Rouy)Nevski is associated with isoenzyme differentiation. The tetraploid form ofH. marinum s.l. exhibited fixed heterozygosity of several heterozymes with one homoeozyme shared with var.fouilladei and the second homoeozyme not found in the two diploids. It also differed from both diploids in the mobility of glucose-6-phosphate dehydrogenase. All three taxa differed in morphs of EST-A. It is concluded that the tetraploid is an allopolyploid with one genome closely related to the diploid var.fouilladei and with the second genome divergent from those of both diploids by genes for unique morphs of eight homoeozymes. On the basis of the isoenzyme data, three phylogenetic sibling species—H. marinum Huds. s.str. (2x),H. geniculatum All. s.str. (= var.fouilladei, 2x), andH. caudatum Jaaska, spec. nova (4x), are proposed within theH. marinum s.l. complex and a key is given.
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  • 54
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    Plant systematics and evolution 191 (1994), S. 227-236 
    ISSN: 1615-6110
    Keywords: Lichenized fungi ; Lecanoraceae ; Lecanora epibryon ; L. subimmersa ; Chemotaxonomy ; biogeography ; taxonomy ; xanthones
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    Notes: Abstract The chemical variation inLecanora epibryon andL. subimmersa, two species of theL. subfusca group, has been examined. In both species the chemical differences are correlated with geographical distribution, but not with morphological differences. As a consequence the chemotypes are recognized at subspecific level. InL. epibryon three chemical races are segregated according to the various chemosyndromes present. Subspeciesepibryon, containing atranorin and triterpenoids, occurs in the northern hemisphere and South America, while the other two subspecies occur only in the southern hemisphere. The subsp.broccha (Nyl.)Lumbsch, comb. nova, contains atranorin, the stictic acid and the 2,5,7-trichloro-3-O-methylnorlichexanthone chemosyndromes, while subsp.xanthophora Lumbsch, subsp. nova, is similar but lacks the stictic acid chemosyndrome. Two chemical races occur in the pantropical speciesL. subimmersa. While subsp.subimmersa contains atranorin and zeorin, subsp.ramboldii Lumbsch & Elix, subsp. nova, contains an additional ten chlorinated xanthones.L. impressa is reduced to synonymy toL. subimmersa.
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  • 55
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    Plant systematics and evolution 191 (1994), S. 247-263 
    ISSN: 1615-6110
    Keywords: Asteraceae ; Senecioneae ; Blennospermatinae ; Ischnea ; Revision ; taxonomy
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    Topics: Biology
    Notes: Abstract The endemic New Guinean genusIschnea F. Muell. (Asteraceae, Senecioneae, Blennospermatinae) is revised and four species are recognized. Characters of special interest are tubeless ray florets, male disc florets, and secretory spaces in leaves. A principal component analysis is made on theIschnea elachoglossa F. Muell. complex which shows great variation. One new species,I. capellana Swenson, from the Star Mountains, is described. A key, illustrations, and distribution maps to all species are supplied.
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  • 56
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    Plant systematics and evolution 192 (1994), S. 11-29 
    ISSN: 1615-6110
    Keywords: Hamamelidae ; Juglandaceae ; rbcL ; phylogeny ; taxonomy
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    Topics: Biology
    Notes: Abstract A cladistic analysis of molecular data from the chloroplast generbcL was used to examine the taxonomic relationships of the walnut family (Juglandaceae). In addition, chemical and morphological data from a previous study byHufford (1992) were incorporated, expanded, and analyzed independently and in combination with the molecular data. The results of these analyses suggest that theJuglandaceae are more closely related to theFagaceae, Betulaceae, Casuarinaceae, andUrticaceae and their relatives (sensuCronquist 1981) than they are to theAnacardiaceae (sensuThorne 1983). However, sequence data fromrbcL also suggest a relationship between the higherHamamelidae and certain families in theRosidae sensuCronquist 1981 (such asRosaceae andRhamnaceae), an outcome which would add credence to the widely accepted view of the polyphyletic nature of theHamamelidae.
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  • 57
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    Plant systematics and evolution 193 (1994), S. 115-123 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Strelitzia ; Heliconia ; Typha ; Benincasa ; Epicuticular wax ; wax ultrastructure ; wax chemistry ; systematics ; taxonomy
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    Notes: Abstract Certain non-liliiflorous taxa within the monocotyledons (e.g.,Strelitzia, Heliconia, Typha) are characterized by compound epicuticular wax rodlets (Strelitzia type). Similar rodlets are also encountered on the surface of the dicotyledonous plantBenincasa hispida (Thunb.)Cogn. Chemical analysis of the surface wax from both sources showed that the rodlets are chemically distinct. The rodlets of the monocotyledons consist exclusively of aliphatic wax lipids, mainly wax esters. In contrast, the rodlets ofBenincasa are cheifly composed of triterpenol acetates and triterpenols. Formation of rodlets is therefore interpreted as ultrastructural convergency. It is concluded that taxonomical studies on wax crystalloids can be misleading when interpreted in terms of micromorphology of crystalloids only.
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  • 58
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    Plant systematics and evolution 182 (1992), S. 149-227 
    ISSN: 1615-6110
    Keywords: Asteraceae ; Heliantheae ; Blepharispermum ; Revision ; taxonomy ; phylogeny ; cladistics
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    Notes: Abstract The palaeotropic genusBlepharispermum (Asteraceae, Heliantheae) is revised for the first time. Fifteen species from Africa, the Arabian Peninsula, Madagascar, India, and Ceylon are recognized. Two new species are described, viz.B. arcuatum andB. canescens. Aspects of the systematic position and morphology of the genus are discussed. A hypothesis of phylogenetic relationships is presented by way of a cladistic analysis. A key to all species in the genus as well as typification, descriptions, drawings and distribution maps are supplied. Chromosome counts of two species are reported.
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  • 59
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    Plant systematics and evolution 180 (1992), S. 1-13 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Triticeae ; Elymus ; Genome analysis ; morphology ; taxonomy
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    Topics: Biology
    Notes: Abstract Seven tetraploid species ofElymus, viz.E. sibiricus, E. caninus, E. gmelinii, E. semicostatus, E. caucasicus, E. parviglume, andE. longearistatus subsp.canaliculatus, representing five sections were studied morphologically and used in interspecific hybridizations. The aim was to investigate whether the present sectional delimitation of the genus was in agreement with genomic data and if there was a correlation between genome constitution and morphology. The study revealed: (i) further information on the genomic affinities between the different species, (ii) that there is no congruence between genome constitution of the species and current sectional delimitation, and (iii) that there is a correlation between genome constitution and morphology in the palea apex shape and in the size of cilia of the palea.
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  • 60
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    Plant systematics and evolution 180 (1992), S. 221-225 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Acanthaceae ; Ruellia ; Speciation over short distances ; endemism ; taxonomy ; Flora of Mexico
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    Notes: Abstract A new section in MexicanRuellia, R. sect.Urceolata comprising three species (includingR. cedilloi, spec. nova), endemic to Mexico, is described and illustrated. The taxonomic relationship and differentiation of the species are discussed. Evolution in Mexican Ruellas seems to be occurring at the diploid level.
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    Plant systematics and evolution 181 (1992), S. 143-169 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Rubiaceae ; Tocoyena ; Hybridization ; differentiation ; speciation ; homogamic complex ; tropical woody plants ; taxonomy ; Flora of South America
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    Notes: Abstract The variation pattern of a large population ofTocoyena formosa in Botucatu, state of São Paulo, Brazil, and of other samples throughout the species area was analysed by morphometrical, statistical, ecological, and phytogeographical methods. Excessive variation and the remarkable coherence of two different character syndromes within this species strongly suggest that it has originated as a homogamic (diploid) hybrid complex. Possible parental species areT. brasiliensis, mainly from the Amazon region, andT. viscidula from the dry caatinga region of NE. Brazil.T. formosa has a much more extensive geographical range and greater ecological plasticity, ranging from the Amazon basin and the Guyanas throughout the Central Brazilian Plateau and from NE. to S. Brazil and Paraguay. Three (partly sympatric) varieties are distinguished withinT. formosa, i.e. var.formosa, var.pseudobrasiliensis (var. nov.), and var.microdon (comb. et stat. nov.). A provisional taxonomic revision, key, and conspectus covers the 12 accepted species ofTocoyena with blunt flower buds and ovate obtuse corolla lobes (group A, includingT. formosa); their distribution is shown in a map.
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    Plant systematics and evolution 181 (1992), S. 217-226 
    ISSN: 1615-6110
    Keywords: Diatoms ; plankton ; Chaetoceros ; New species ; morphology ; taxonomy
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    Topics: Biology
    Notes: Abstract Two new planktonic diatom species of the genusChaetoceros are described herein:Ch. octagonus andCh. rectus, from material of Baja California coasts and the Gulf of California, respectively;Ch. rectus was also found in a sample from Australian waters.Ch. octagonus is a robust species, with a characteristic pyramidal valve shape, heavily silicified valves and setae, and one central rimoportula on every valve in the chain; it is compared with related species, which show a similar morphology, especially by electron microscopy. It belongs into subg.Chaetoceros, sect.Borealia. Ch. rectus is placed in subg.Hyalochaete, and provisionally within sect.Anastomosantia. Its major characters are: chains, cells, and setae are delicate and fragile, cells are joined in the chain by a “bridge” which connects sibling intercalary setae, valves and setae are weakly silicified, and one rimoportula is present on terminal valves only. Comparison is made with another species of the same section.Ch. rectus shows a different manner of chain-forming within the genus than previously described in the literature.
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    Plant systematics and evolution 181 (1992), S. 255-260 
    ISSN: 1615-6110
    Keywords: Pyrenocarpous lichens ; Verrucariaceae ; Dermatocarpon ; Catapyrenium ; Catapyrenium velebiticum comb. nov. ; Catapyrenium pyrenaicum spec. nova ; Systematics ; taxonomy ; Flora of Austria, Croatia, France, Spain, and Switzerland
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    Notes: Abstract Catapyrenium pyrenaicum is described as new from northern Spain and adjacent France, and the new combinationCatapyrenium velebiticum is made. The new species differs fromC. velebiticum mainly in its laminal pycnidia. Remarks on taxonomy, ecology, and distribution of the species are given.
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    Plant systematics and evolution 184 (1993), S. 207-231 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Ericales ; Cladistics ; phylogeny ; taxonomy
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    Notes: Abstract A cladistic analysis of theEricales based on morphological, anatomical, embryological, and phytochemical data has been undertaken. Resulting from the analysis, 56 equally parsimonious cladograms were obtained. The tribeEnkiantheae was found to be the sister-group of the rest of theEricaceae, in which theEmpetraceae, theEpacridaceae, Pyrolaceae, andMonotropaceae are forming derived ingroups. It is thus concluded that theEricaceae are a paraphyletic assemblage as presently circumscribed, and thatEmpetraceae andEpacridaceae are better treated as members of theEricaceae.
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    Plant systematics and evolution 185 (1993), S. 17-33 
    ISSN: 1615-6110
    Keywords: Pyrenocarpous lichens ; Verrucariaceae ; Catapyrenium ; Dermatocarpon ; Catapyrenium analogicum spec. nova ; C. andicolum spec. nova ; C. chilense comb. nov. ; C. corticolum comb. nov. ; C. exaratum spec. nova ; C. lachneoides spec. nova ; C. podolepis spec. nova ; C. ruiz-lealii comb. nov. ; C. squamulosum var.argentinum comb. nov. ; Systematics ; taxonomy ; Flora of Argentina ; Bolivia ; Brasilia ; Chile ; Ecuador ; Paraguay ; Peru ; Uruguay
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    Notes: Abstract 13 species of the lichen genusCatapyrenium are reported from South America. Five species (C. analogicum, C. andicolum, C. exaratum, C. lachneoides, andC. podolepis) are described as new. A key to the species known from South America is presented. Remarks on taxonomy, ecology and distribution of the species are given.
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    Plant systematics and evolution 185 (1993), S. 91-97 
    ISSN: 1615-6110
    Keywords: Lamiaceae ; Nepetoideae ; Ocimeae ; Isodon ; Plectranthus ; Pyramidium ; Rabdosiella ; Systematics ; taxonomy
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    Notes: Abstract The two generaPlectranthus andIsodon are compared and found to be very dissimilar.Isodon ist considered to be misplaced inOcimeae subtribePlectranthinae and apparently is more closely related to subtribeHyptidinae. The disjunct genusRabdosiella is compared to these two genera and regarded to be polyphyletic. The AfricanR. calycina (Benth.)Codd is returned toPlectranthus and calledP. calycinus Benth., while the AsianR. ternifolia (D. Don)Codd is placed inIsodon sect.Pyramidium and calledI. ternifolius (D. Don)Kudo.
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  • 67
    ISSN: 1615-6110
    Keywords: Gymnosperms ; Pinaceae ; Pinus ; Seed storage proteins ; electrophoresis ; taxonomy
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    Notes: Abstract Electrophoretic studies on seed storage proteins of various gymnosperm species showed that both salt soluble and insoluble protein fractions give taxonomic information. Among species of the genusPinus evident differences are found between the subgeneraHaploxylon (Strobus) andDiploxylon (Pinus). In sect.Strobus the two subsectt.Strobi andCembrae are readily distinguished fromP. bungeana (sect.Parrya) which appears to fall in an intermediate position between haploxyl and diploxyl pines. Among the species of subg.Diploxylon, “mountain pines” show very similar protein patterns in agreement with their recent speciation (Quaternary).
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    Plant systematics and evolution 186 (1993), S. 95-122 
    ISSN: 1615-6110
    Keywords: Polygonaceae ; Persicarieae ; Rubrivena ; Persicaria sect.Rubrivena ; P. wallichii var.wallichii (=Polygonum polystachyum) ; P. wallichii var.tomentosa ; var. nov. ; P. pinetorum ; Anatomy ; micromorphology ; pollen morphology ; cladistics ; heterostyly ; taxonomy ; Flora of Himalaya
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    Notes: Abstract Morphological and anatomical characters (including pollen morphology) of the genusRubrivena are described. The phylogenetic relationships ofRubrivena, the putatively related genusKoenigia and the four sections of the genusPersicaria are analyzed by the application of cladistic methods.Persicaria s. str. turns out to be paraphyletic; however, inclusion ofRubrivena produces a clade which is marked by five synapomorphies (e.g., long styles, semitectate reticulate pollen grains and some seed characters). In order to eliminate the paraphyly ofPersicaria as well as to avoid nomenclatural changes of all taxa of sect.Cephalophilon, Rubrivena is included in the genusPersicaria. Sect.Rubrivena differs from the other sections in pollen morphology [granulated muri and 6 (–7)-zonocolpate aperture system] and inflorescence type (well-branched panicles). In addition, heterostyly is confirmed inPersicaria wallichii, and is reported here also forP. pinetorum. Keys and descriptions are provided for all taxa and a distribution map is given. Two species are illustrated by line drawings. One new variety,Persicaria wallichii var.tomentosa, is described. Five lectotypes are selected.
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    Plant systematics and evolution 189 (1994), S. 165-191 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Rutaceae ; Zanthoxylum ; Fagara ; Flower morphology ; perianth ; gynoecium ; acrostylous and anacrostylous-basistylous carpels ; compitum ; taxonomy
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    Notes: Abstract The question whether the uniseriate perianth ofZanthoxylum L. s. str. is homologous with the calyx or the corolla of taxa included inFagara, or of an independent origin, has been controversial for a long time, but the arguments mostly have remained theoretical. The present investigation of floral structures indicates that there are two different types of uniseriate perianth inZanthoxylum s. str. Therefore, this taxon does not represent a natural group and should be united withFagara asZanthoxylum s.l. The infrageneric taxonomy of this genus is still very ambiguous. It is shown that differences in indumentum, number of sepals and petals (5-4-3) resp. perianth segments (4–9), stamens (3–6), and free carpels (1–5) are of systematic relevance. Particularly important but so far neglected is carpel shape, where an acrostylous and an anacrostylous-basistylous type can be recognized. Stigmata of 2 or more carpels mostly fuse to form a compitum. 4–5-merous flowers with calyx and corolla, and acrostylous carpels are considered as plesiomorphic character states in the genus. On the basis of ± corresponding morphological and phytochemical progressions a working hypothesis about the relationships withinZanthoxylum s.l. is presented in graphical form (Fig. 9).
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    Plant systematics and evolution 191 (1994), S. 111-126 
    ISSN: 1615-6110
    Keywords: Colchicaceae ; Androcymbium ; Allozymes ; evolution ; taxonomy ; genetic conservation
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    Topics: Biology
    Notes: Abstract Levels of allozymic and morphological diversity amongAndrocymbium gramineum, A. europaeum, andA. psammophilum have been assessed using data on 17 allozyme loci and 18 morphological characters. No apparent pattern of geographic or ecological variation was found. Our results also suggest thatA. gramineum andA. europaeum should be considered members of a single species and that the insular speciesA. psammophilum can no longer be thought of as the result of a founder effect fromA. gramineum. Intrapopulational variability was greater than inter-populational variability at both levels studied, which is of strategic interest for the “ex-situ” conservation of these threatened endemic species.
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  • 71
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Bovine milk ; Multivariate optimization ; Glycerophospholipids ; Molecular species separation ; Chemometrics
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    Topics: Chemistry and Pharmacology
    Notes: Summary The molecular species profile, representing the fatty acid combinations on the glycerol backbone, is the most fundamental description of an intact glycerophospholipid class and provides a key to understanding its functional characteristics. We have developed a powerful RP-HPLC method for the separation of molecular species, including so-called “critical pairs”, of natural mixtures of 1,2-diacyl-sn-glycero-3-phosphocholine 1,2-diacyl-sn-glycero-3-phosphoethanolamine from bovine milk and other natural sources. We have used a novel multivariate development and optimization strategy to locate the region of optimum separation conditions within a prechosen domain of the chromatographic parameter space.
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  • 72
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Open tubular columns ; Cross-linked polyacrylate stationary phase ; Photopolymerization ; Antracene derivatives
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    Topics: Chemistry and Pharmacology
    Notes: Summary Polyacrylate films containing a lauryl moiety were fabricated on about 12 μm I.D. fused silica capillaries by in-situ photopolymerization of acrylates. Relatively thick films up to 1 μm were obtained by the technique. The films were tested as retentive layers for reversed phase open tubular liquid chromatography (OTLC). Due to the presence of the incorporated lauryl moiety in the layer considerable retention could be achieved for polar compounds with aqueous mobile phases. The efficiency of the prepared columns approximates to the theoretical value. The polyacrylate films appear to be extremely stable even under strong basic conditions. The films swell considerably in the presence of nonpolar solvents resulting in more favourable retention and a significant improvement of the chromatographic performance.
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    Chromatographia 35 (1993), S. 627-630 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Fatty acid analysis ; Fish oils
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    Topics: Chemistry and Pharmacology
    Notes: Summary A chromatographic method has been developed for the determination of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in fish oil dietary supplements containing triglycerides rich in (n−3) polyunsaturated fatty acids (PUFAs). Following the ester saponification, free fatty acids were resolved by TLC into two fractions: i) a more mobile group of saturated and monounsaturated fatty acids and ii) a less mobile group containing PUFAs. The PUFA fraction was further analyzed by HPLC to determine the levels of EPA and DHA in the fish oil sample.
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  • 74
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Carbidopa and levodopa in plasma ; Electrochemical detection
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    Topics: Chemistry and Pharmacology
    Notes: Summary A validated reversed-phase high-performance liquid chromatographic procedure employing electrochemical detection (LCEC) for the analysis of carbidopa and levodopa in human plasma is reported. The method is sensitive and specific with amperometric detection at a glassy carbon working electrode with Eapp=0.75 V vs. Ag/AgCl. The retention times of levodopa, internal standard, and carbidopa are 3.3, 4.5, and 9.7 minutes, respectively, with an overall chromatographic run time of 12.0 minutes. The peak height ratio versus plasma concentration is linear over the range of 5.0 to 500 ng/mL for each analyte and exhibits correlation coefficients of 0.9957 or better (n=9). The mean absolute recovery of carbidopa and levodopa using the described assay is 36.6 and 66.0%, respectively. The inter- and intra-day accuracy and precision are within 11.8% of the actual values for all concentrations. Also, due to the demonstrated instability of carbidopa and levodopa in plasma a procedure is provided to circumvent this. Blood collected in pre-treated Vacutainer tubes can be stored in an ice bath for up to 4 hours without any significant degradation, thereby providing a practical means for processing several clinical samples simultaneously.
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  • 75
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Fullerenes ; FullereneSep® ; Separation factor ; HPLC-particle beam mass spectrometry
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    Topics: Chemistry and Pharmacology
    Notes: Summary High-performance liquid chromatographic separation of fullerene mixtures in the range C60 to C100 can be achieved using a novel stationary phase which rivals the performance of the more expensive ‘Pirkle-type’ columns currently employed.
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    Chromatographia 35 (1993), S. 675-678 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Ion chromatography ; Trace metal determination ; Sample contamination ; Human hair
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    Topics: Chemistry and Pharmacology
    Notes: Summary The dynamic ion-exchange chromatographic analysis of bivalent ions, such as Cu, Pb, Zn, Ni, Co and Mn in resistant organic matrices needs preliminary wet ashing with oxidizing acids (HNO3 and HClO4). Such treatment may lead to an increase in the amounts of metals present in the sample due to their release from containers or equipment used in an acidic environment and to metal impurities contained in the acids. The effect of these interferences in the determination of trace metals in human hair was studied.
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  • 77
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Normal phase separations ; Cyanopropyldimethyl silica ; Chloro-added polycyclic aromatic hydrocarbons ; Environmental samples
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    Topics: Chemistry and Pharmacology
    Notes: Summary Retention characteristics in normal phase HPLC of highly biologically active chloro-added polycyclic aromatic hydrocarbons (PAHs) were studied. Silica, cyanopropyldimethylsilyl- and aminopropylsilyl- modified stationary phases were investigated. Retention properties of chloroadded PAHs on these phases were shown to be strongly influenced by the number of chloro-additions. This is due to the strong polarity of the methylene carbon at the chloro-addition site. Active silica had a strongly degrading effect on the unstable chloro-added PAHs during separation. Aminopropylsilica did not exhibit sufficient selectivity towards chloro-added PAHs when compared to chlorosubstituted PAHs. Cyanopropyldimethylsilica was shown to be applicable to a group separation of chloro-added and chloro-substituted PAHs. A fast clean-up procedure for chloro-added PAHs in complex samplesis outlined. It involves an initial elimination of more polar substances on a short open column with strongly deactivated silica and a subsequent separation on a cyanopropyldimethylsilyl HPLC column in normal phase mode.
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  • 78
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    Chromatographia 32 (1991), S. 345-349 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Column packings ; Pore size distribution ; Diffusion and adsorption ; Band broadening
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The complex intraparticle structure typical of chromatographic column packings has been analyzed by use of an equivalent network model which emphasizes pore size distribution and connectivity. Special attention is given as to the way in which diffusion and adsorption interact and display modified peak spreading characteristics according to the morphology of the pore space. This study reveals a very significant increase in the column band broadening over that expected from physical adsorption which can arise from particular distributions of pore sizes. This has implications for designing packings which take advantage of the separating power due to adsorption but do not compromise the resolution of the chromatographic system.
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  • 79
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; GC/ECD detection ; PCBs, ortho and non-ortho ; Chromatographic separation ; Congener determination ; FTIR identification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An analytical procedure for the individual determination of ortho and non-ortho PCB congeners in sediments, using high performance liquid chromatography (HPLC) preseparation and gas chromatography/ECD detection, is described. Gas chromatography/FTIR spectrometry (GC/FTIR) and gas chromatography/mass spectrometry (GC/MS) were employed for individual congener identification and determination. Sample extraction, clean-up of extract and selective elution procedures were optimized by using reference certified marine sediment samples. Recovery and precision were typically 83% and 16% respectively at 2 ng/g of total PCB content. The proposed procedure, tested by analyzing real sediment samples, showed a reproducibility better than 20% at 13 ng/g PCB level.
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  • 80
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Glutamine ; Pyroglutamic acid ; Amino acids formulations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The aminoacid glutamine in aqueous solution and in conditions of high temperature and long term storage is partly transformed into pyroglutamic acid which exhibits potential neurotoxic effects. Commercially available aminoacid mixtures supplemented with glutamine are heat-sterilized and some losses of glutamine and formation of pyroglutamic acid may occur. The aim of the work was to set up an easy and reliable HPLC method which allows the determination of pyroglutamic acid as a degradation product of glutamine. The column was a 5 μm Hypersil ODS (100×4.6 mm) and the mobile phase 100% 0.007 M phosphate buffer pH 3.5. Stability studies in different conditions of temperature and time of storage were performed on aminoacid mixture available in the commerce.
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  • 81
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Carbonyl compounds ; Luminarin hydrazides ; Fluorescence detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Fluorogenic reagents (luminarin 3, luminarin 11 and luminarin 12), having a quinolizinocoumarin moiety as fluorophore and a carboxylic acid hydrazide function as reacting group, have been developed. These reagents were found to be highly sensitive fluorescence derivatization reagents for aldehydes and ketones in high-performance liquid chromatography. The reagents readily react with carbonyl compounds in aqueous sulphuric acid solution (0.1 M) at room temperature to produce the corresponding hydrazone derivatives, which can be separated on both reversed or normal-phase column. The structures of the derivatives were studied, together with their properties in reversed and normalphase chromatographic systems. UV absorbance, corrected fluorescence spectral data and quantum yields of luminarin 3, luminarin 11 and luminarin 12 are presented. The detection limits (signal to noise ratio=3) for aldehydes and ketones were in the sub-pmol range. Luminarin 3 was also applied to the determination of hydroxymethylfurfural (HMF) in orange juices and concentrates. The method for HMF involves the solid-liquid extraction of the juice by using a C-18 cartridge prior to derivatization and normal-phase separation of the derivative with fluorimetric detection at 387 nmex., 444 nm em. The calibration curve was linear for amounts of HMF ranging from 0.1 to 10 nmol. Intrarun relative standard deviation was 12.8% for 0.1 nmol and 2.6% for 1 nmol. Recovery studies indicated an average of 98.7±1.9% for juice concentrate and 99.8±3.2% for pasteurized juice.
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  • 82
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Method development ; Chemometrics ; Response criteria ; Analysis of drug purity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Optimization procedures require adequate response criteria to assess the quality of each chromatogram obtained during the process. The objective of this paper is to evaluate the possibility of using different resolution functions, in the chromatographic separation of a drug and its impurities (particularly the impurity just eluted after the drug). This study shows the limits of some resolution expressions. The interest of the simple Δt criterion, the difference between retention times, is presented in this paper.
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  • 83
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    Chromatographia 36 (1993), S. 147-151 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Polarity ; Retinoids
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    Topics: Chemistry and Pharmacology
    Notes: Summary The retention of retinoids in reversed-phase liquid chromatography was studied using aqueous mobile phases of different composition (methanol 94–86% and acetonityrile 92–82%) at five temperatures (40–60 °C). With both organic modifiers the effect of the molecular structure increased as the water content and the polarity of the mobile phase increased. The temperature-dependence increased in the same manner with aqueous acetonitrile mobile phases. The π-π interactions between the retinoids and acetonitrile diminish when the water content of the mobile phase is increased, as happens also to the hydrophobic interactions with both organic modifiers. The net effect of these changes depends on the composition of the mobile phase. There was excellent correlation of retention with all polarity parameters studied(ϕ, P′, xe, xd, xn, E T N , δT, δ, δo and δd), when the calculations were made separately with methanol and acetonitrile. The volume fraction of the organic modifier, ϕ, was the only parameter describing the retention well in both organic modifiers simultaneously.
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  • 84
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Aromatic amines ; Arylbenzylamide methylthioether derivative ; SL 85.1016 ; Pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An HPLC method has been developed for the determination of SL 85.1016, a new calcium antagonist arylbenzylamide methylthioether derivative. SL 85.1016 and the internal standard, SL 87.0210, are extracted from alkaline human plasma withn-hexane and back extracted into 0.05 M phosphate buffer (pH 2.5; 0.2 ml). Acetonitrile (50 μl) is added to the final aqueous extract in order to prevent absorption of the compounds of interest onto the walls of the glass tube; this solution then is partially processed by HPLC on a C18 column with UV detection (254 nm). The determination limit of the method is 2 ng.ml−1 of SL 85.1016 in human plasma; the response to the drug is linear in the range 2–200 ng.mg−1.
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  • 85
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    Chromatographia 36 (1993), S. 347-350 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Allium ; Derivatization ; S-alk(en)yl-L-cysteine sulfoxides ; Sulfur amino acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Two pre-column derivatization procedures coupled with reversed phase HPLC have been compared for the analysis ofS-Alk(en)yl0L-cysteine sulfoxides in variousAllium species. In order to establish external standards some (+/-) sulfoxides were synthesized, using a new method to enhance asymmetric synthesis of the diastereoisomers. The first derivatization method is the formation ofo-phthaldialdehyde/tert.-butylthiol derivatives which can be analyzed using UV detection. The second, presently used for amino acid analysis, is the Waters Pico-Tag method, which employs phenylisothiocyanate as derivatization reagent. As the Pico-Tag method was found to be the most efficient for determination ofS-alk(en)yl-L-cysteine sulfoxides it was used to determine the alliin content of various samples of garlic.
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  • 86
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Fatty acids and bile acids ; Fluorogenic precolumn derivatization ; 2-Bromoacetyl-6-methoxynaphthalene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The use of 2-bromoacetyl-6-methoxynaphthalene as a fluorogenic labelling reagent in pre-column derivatization for the HPLC separation of biologically active carboxylic acids (fatty acids and bile acids) has been investigated. The compound reacts (30 min. at 70°C) with carboxylic acids to give fluorescent esters that can be separated by reversedphase HPLC and detected at λ ex. 300 nm, λ em. 460 nm. The experimental conditions for the derivatization and chromatographic separation are discussed. Applications to the determination of valproic acid and chenodeoxycholic acid in pharmaceutical formulations are described.
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  • 87
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Valproic acid ; Simultaneous determination of anticonvulsants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The derivatizing procedure of Moody et al. [20] for valproic acid has been simplified and applied to the simultaneous HPLC determination of valproic acid (VPA), barbital (B), primidone (PRM), phenobarbital (PB) and carbamazepine (CBZ) in serum or plasma of epileptic patients. The sample is deproteinized with acetonitrile containing esterification agents and an aliquot of the supernatant is heated to 70°C for 15 min with 4-bromophenacyl bromide. The reaction mixture is analysed on a C18 column at ambient temperature, with gradient elution and with detection at 205 nm. The time required for the chromatographic analysis is 13 min; identification is based on retention time and quantification is by peak area determination with an internal standard. The calibration curves show good linearity in the range 6.25 to 100 mg/L. The detection limits at a signal: noise ratio ≥3, ranged from 1 mg/L for B and CBZ to 2–3 mg/L for PRM, PB and VPA. The method described for the simultaneous determination of the five drugs in the same plasma pool, correlated well with isocratic HPLC methods specific for each drug. The simultaneous procedure described allows a reproducible (CVs≤6.5% within run) and rapid (25 min for sample preparation: 13 min for chromatographic run) therapeutic monitoring of patients treated with VPA and two or more antiepileptic drugs.
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  • 88
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Porous polymer spherical packings ; Vinyl ether ; Alkali resistance ; No abnormal adsorption
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    Topics: Chemistry and Pharmacology
    Notes: Summary Spherical, porous-polymer particles for column packing in high-performance liquid chromatography were prepared by suspension copolymerization of alkylvinyl ether with triethyleneglycol divinyl ether. The hydrophobicity of the packings was easily adjusted by changing the monomer ratio. The packings showed the usual reversed-phase liquid chromatographic properties, but did not sho abnormal retention, tailing and broadening of peaks and irreversible adsorption of ionic and aromatic substances, owing to the lack of ionic or aromatic groups. In addition, the packings were stable in alkaline solutions because of the relative alkali stability of C−O−C bonds as compared with CO−O and Si−O−C bonds in conventional packings.
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  • 89
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Anion exchange ; Indirect photometric and direct conductivity detection ; Naphthalenesulfonate ; Inorganic anions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Indirect photometric and unsuppressed direct conductivity detection modes are examined using naphthalene mono-, di-, and tri-sulfonate as mobile phases for the separation of several anions such as F−, Cl−, NO2 −, Br−, NO3 −, SO4=,I−, and SCN− using a commercial anion exchange column. With all three mobile phases, conductivity detection shows better sensitivities and detection limits than indirect photometry. Conductivity detection is 5 to 16 times more sensitive than indirect photometry for all analytes. Detection limits achieved using these mobile phases are, for example, 0.04 ng and 0.1 ng for chloride ion with conductivity and indirect photometry, respectively. Both detection modes give wide linear ranges extending from at least 100 ppm to the detection limit of each anion which is generally about 0.02 ppm. Sulfur oxide anions such as dithionate and tetrathionate are separated using flow programming with naphthalenetrisulfonate as the mobile phase in less than 20 minutes. With both detection modes, desired chromatographic performance of these three eluents is achieved without pH adjustment of the mobile phase.
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  • 90
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Heat-treated milk ; Milk quality indicators ; 5-Hydroxymethyl-2-furfuraldehyde
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An enhanced method of HPLC for the determination of 5-Hydroxymethyl-2-furfuraldehyde (HMF) in fluid milk was perfected. Its resolving capacity permitted the specific separation of this compound. The real concentration (μmol/l) of HMF was determined and not the HMF value, as in the colorimetric analysis, where an intermediary coloured compound (HMF-TBA) is utilised. The optimum pH condition (pH=4.0–4.2) for the mobile phase to prevent overlapping between the HMF peak and the peaks of the other compound (α and β) that coeluted with the HMF and also the optimum organic solvent content (3% or 7%) were established. This is a sensitive, quick and safe method for the determination of HMF in fluid milk.
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  • 91
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chlortetracycline ; Reversed-phase silical gel ; C8 bonded phase ; Collaborative study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An established method for the analysis of chlortetracycline by liquid chromatography using octylsilylated silica gel as the stationary phase was examined in a multicentre study involving five laboratories and a total of six columns. Three chlortetracycline hydrochloride samples were analysed. The main component and the impurities were determined. An analysis of variance, treating each column as a different laboratory, showed an absence of consistent between-laboratory bias and the presence of a significant laboratory-sample interaction. The repeatability and the reproducibility of the method, expressed as relative standard deviations of the result of the determination of chlortetracycline hydrochloride, were calculated to be 0.9% and 1.1% respectively.
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  • 92
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    Chromatographia 37 (1993), S. 627-634 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; ODS phases ; NMR and FTIR characterization ; Stationary phase functionality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Two spectroscopic methods, solid state NMR and diffuse reflectance FTIR, have been used in conjunction with liquid chromatographicretention data to identify and distinguish the functionality of octadecylsilica (ODS) stationary phases. NMR and FTIR spectra are indicative of various features of the different functionalities of the phases and this information can be used to elucidate the configuration of the organosilyl moiety in the ODS on the silica surface and explain why DSS phases have different molecular shape (mainly planarity) recognition capability.
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  • 93
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    Chromatographia 37 (1993), S. 423-428 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Polymer-modified silica ; Polypyrrole cloride ; Polypyrrole dodecylsulfate ; Small molecules ; Polyaromatic hydrocarbons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Polypyrrole chloride and polypyrrole dodecylsulfate coated-silica packing materials have been synthesized. Reverse-phase chromtographuy was employed to characterise both packings. A series of test compounds with known properties was used as molecular probes. They included benzene and derivatives, basic drugs, and polyaromatic hydrocarbons. A commericial C18 column was also used for the purpose of comparison in some cases.
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  • 94
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Arsenic compounds ; Polymeric styrene divinylbenzene phase ; Ion-pairing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The resolving power of an ion-pair reversed-phase liquid chromatography method, on a polymeric stationary phase (PRP-1) with an alkaline aqueous mobile phase (pH=9) containing tetrabutylammonium cation as ion-pairing agent, is compared with a traditional ion-pairing system using an octadecyl-modified silica column and a neutral aqueous mobile phase (pH=7.3). This chromatographic system (PRP-1 column) provides a rapid means for the determination of two of the most important arsenic species, arsenobetaine and arsenite. Addition of methanol (5%) to the aqueous mobile phase allows the differentation of arsenobetaine from the system peak when using UV detection.
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  • 95
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Gravity-flow column chromatography ; Provitamin A determination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The provitamin A content of some food samples was determined by methods involving MgO: Hyflosupercel gravityflow column chromatography (GFCC) and reversed phase high performance liquid chromatography (HPLC), the quantitation being done by external standardization (HPLC-ES) or internal standardization (HPLC-IS) with Sudan. The results obtained with α- and β-carotene in carrots, β-carotene and β-cryptoxanthin in papaya and β-carotene in tomato and kale agreed well, showing that any of the these techniques can be used, provided the analysis is done under optimum conditions. Good separation of the different provitamins using GFCC depends on the analyst's skill and visual acuity. HPLC-ES required a constant supply of provitamin standards, thus the varying purity of commercially available standards and the high instability of these compounds could pose grave problems. Due to the stability of Sudan, HPLC-IS appeared to be the method of choice although passage of the extract through a MgO: Hyflosupercel minicolumn was required prior to injection to separate chlorophylls, dihydroxy- and polyoxycarotenoids which would otherwise elute with Sudan. Nonconformity of the Sudan structure to those of the provitamins did not effect the quantitative results. The chromatographic separation, identity and quantification of the provitamins could be more easily established by using HPLC-IS, complemented with GFCC.
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  • 96
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    Chromatographia 33 (1992), S. 103-112 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Gas chromatography ; Chiral separations ; Allethrin ; Cypermethrin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Liquid and gas chromatographic separations of the pyrethroid insecticides allethrin and cypermethrin have been investigated with various achiral and chiral stationary phases. Diastercomeric and enantiomeric selectivity was observed for cypermethrin on a Pirkle-type chiral LC stationary phase, but very strong interactions and therefore long retention times prevented the separation of allethrin on this phase. Trans-allethrin isomers were separated on a chiral β-cyclodextrin RP-HPLC column while cypermethrin showed some difficulties on this phase due to isomerization. Diastereomeric but no enantiomeric selectivity by GC was achieved for cypermethrin with an apolar DB 5 capillary. GC separation of the diastereomers was used to study the selective photodegradation of cypermethrin isomers after forestry applications. Chiral β-cyclodextrin-based GC phases showed some enantioselectivity for cis- and trans-allethrin isomers. A separation of the eight isomers into six partially resolved peaks was achieved by GC with a coupled column consisting of chiral permethylated β-cyclodextrin and DB 1701 as stationary phases. This combination was used to characterize allethrin formulations intended for indoor use and to investigate allethrin products formed by ozonolysis of thin films of the insecticide.
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  • 97
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chiralcel OD ; N-Alkyl-N-methylanilineN-oxide enantiomers ; Chiral nitrogen centre ; Flavin-containing monooxygenase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A high-performance liquid chromatographic method for the resolution of the enantiomers of a series ofN-alkyl-N-methylanilineN-oxides is reported. The resolutions were achieved using a Chiralcel, OD chiral stationary-phase with a mobile-phase of hexane and ethanol in varying proportions. The chromatographic order of elution of the enantiomers ofN-ethyl-N-methylanilineN-oxide was determined to be (+)-(R) before (−)-(S).
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  • 98
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    Chromatographia 37 (1993), S. 539-542 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Sotolon ; Vin jaune ; Flor-sherry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Sotolon (4,5-dimethyl-3-hydroxy-2(5H)-furanone) is a key flavour compound in the french flor-sherry “Vin jaune”. This compound was determined quantitatively by extraction of 25 ml of wine on a XAD-4 resin, elution with diethyl ether, separation by HPLC on a Lichrospher 100 Diol column, elution with dichloromethane/hexane (60/40) and UV detection at 232 nm. The amount of sotolon in “Vin jaune” (120 to 268 μg/l) was related to the development of the yeast film over a period of 6 years. Only 6 to 51 μg/l were found in the “Vin de paille” which is made with overmaturated grapes of the same Savagnin vine-plant but without development of yeasts, and 80 to 140 μg/l in “Tokai” which are partly grown under a yeast film.
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  • 99
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Column-switching ; Determination of triamterene ; Fluorescence detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A liquid chromatographic method incorporating column-switching and fluorimetric detection for the determination of triamterene in untreated urine, is described. The urine samples (5 μL) were directly introduced onto an Hypersil ODS-C18, 30 μm (20 mm×2.1 mm I.D.) pre-column. Polar urinary compounds were removed by flushing the pre-column with water for 1 min, and the analyte was then switched onto an HP-LiChrospher RP C18,5 μm (125 mm×4mm ID) analytical column using an acetonitrile/phosphate buffer gradient elution. Fluorescence detection was performed at 230 nm excitation and 430 nm emission wavelengths. The recovery of drug was 102±2% in the 0.10–20.0 μg/mL concentration range, the limit of detection being 5 ng/mL. A validation of the usefulness of this procedure was accomplished by analysing urine extracts obtained from real samples.
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  • 100
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Characterization of reversed phases ; Column hydrophobicity ; Column hydrophylicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The validity of a method for characterizing stationary phases for reversed-phase, liquid chromatography, based on the use of homologous series, has been evaluated. The method is based on a retention model which describes the dependence of the logarithm of the capacity factor on mobile phase composition and the carbon number of specific homologous series. A first-order as well as a second-order version of this model was investigated. The second-order model proved to be a significant improvement on the first-order model, even for smaller mobile-phase ranges. Nevertheless both models showed a significant lack of fit, reflecting the incompleteness of these models. Therefore, it is very questionable whether this method is suitable to describe HPLC-column characteristics like hydrophobicity and hydrophylicity.
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